Wood chipper



May 21, 1968 H. J. EKLUND ET AL 3,384,311

WOOD CHIPPER Filed July 26, 1966 I N VEN TOR.

F/K/ y Deal? ,MY M

United States Patent 3,384,311 WOOD CHIPPER Henrik J. Eklund, Pittsfield, Mass., and Dean W. Shields, Birmingham, Ala., assignors to Beloit Corporation, a

corporation of Wisconsin Filed July 26, 1966, Ser. No. 568,002 7 Claims. (Cl. 241-56) This invention relates to a wood chipper and has for an object the provision of apparatus in which the chips are removed continuously from the chipper as they are cut by -a combination of forces consisting of the kinetic energy possessed by the moving chips in a chip receiving chamber, and the blowing action of a moving stream of air adjacent the chips within the chip receiving chamber, and the blowing action of a blower which communicates with a plenum chamber that surrounds the chip receiving chamber and delivers air into engagement with the moving stream of chips as the chips are introduced into a discharge conduit.

A more specific object of our invention is to provide a rotary wood chipper in which an angular portion thereof, as viewed in the direction of rotation, serves as a blower for introducing air into the chip receiving chamber and the plenum chamber while another angular portion thereof performs the function of a chipper.

A further object of our invention is to provide a wood chipper of the character designated in which an effective blower and a plenum chamber therefor is provided outwardly of the chip receiving chamber and is so constructed that the chips do not enter the plenum chamber and are not engaged by the air conveyed therethrough until the chips enter the discharge conduit for the apparatus.

A still further object of our invention is to provide a wood chipper of the character designated which shall be extremely simple of construction, economical of manufacture and one in which all of the air and chip conveying blades are mounted at one side of a disc-like member which is positioned inwardly of an arcuate wall that separates the chip receiving chamber from the plenum chamber.

Briefly, our improved wood chipper embodies a rotary disc having angularly spaced knives and angularly spaced passageways therethrough, together with means to feed wood to one side of the disc whereby the wood is cut into chips which pass through the passageways to the other side of the disc. An outer housing surrounds said other side of the disc and is spaced radially and outwardly from the periphery of the disc. An arcuate wall section surrounds a portion of said other side of the disc inwardly of the outer housing to thus define a chip receiving chamber inwardly of the arcuate wall section and a plenum chamber between the arcuate wall section and the outer housing. Angularly spaced blades are carried by the disc in position to rotate within the arcuate wall section to convey chips through the chip receiving chamber and introduce air into the chip receiving chamber and the plenum chamber. Discharge outlets are provided for the chip receiving chamber and the plenum chamber whereby the air discharged from the plenum chamber engages the moving stream of chips discharged from the chip receiving chamber to thus aid in removing the chips from the chipper as they are cut, thereby eliminating carry-over of the chips.

Apparatus embodying features of our invention is illustrated in the accompanying drawing, forming a part of this application, in which:

FIG. 1 is a perspective view of the wood chipper;

FIG. 2 is an enlarged, vertical section-a1 view through the wood chipper;

3,384,311 Patented May 21, 1968 FIG. 3 is a sectional view taken generally along line 3-3 of FIG. 2; and

FIG. 4 is a fragmental view taken generally along the line 4-4 of FIG. 3.

Referring now to the drawing for a better understand ing of our invention, we show a power unit 10, such as an electric motor, having a drive shaft 11. Opposite ends of the drive shaft 11 are supported in a manner well understood in the art by bearing members 12, only one of which is shown. The bearing members 12 are supported by a supporting frame 13, as shown in FIG. 1.

Mounted on the shaft 11 and adapted for rotation therewith is a rotary disc 14 having a plurality of angularly spaced knives 16 mounted at one side thereof, as shown in FIG. 2. A plurality of angularly spaced through passageways 17 are provided adjacent the knives 16 whereby the wood cut into chips by the knives 16 passes through the passageways to the opposite side of the disc 14.

Surrounding the other side of the disc 14 or the side thereof opposite the knives 16 is an outer housing 18. As shown in FIGS. 2 and 3, the outer housing 18 is spaced radially and outwardly from the periphery of the disc 14. As shown in FIG. 3, the outer housing 18 is provided with side walls 19 and 21 which are spaced from the shaft 11. A centrally disposed inlet opening 22 is provided in the side wall 19 whereby air is drawn inwardly of the housing by means to be described hereinafter.

An arcuate wall section 23 surrounds a portion of the side of the disc 14 opposite the side thereof carrying the blades 16. As shown in FIGS. 2 and 3, the arcuate wall section 23 is spaced inwardly of the outer housing 18 to define a chip receiving chamber 24 inwardly of the arcuate wall section 23 and a plenum chamber 26 between the arcuate wall section 23 and the outer housing 18. That is, the chip receiving chamber is defined by the arcuate wall section 23, the side wall 19 and the adjacent side of the disc 14, as shown in FIG. 3.

Angularly spaced, radially extending blades 27 are secured rigidly to the side of the disc 14 opposite the side thereof carrying the knives 16 by suitable retaining bolts 28. The outer ends of the blades 28 are curved outwardly in the direction of rotation of the disc 14, as shown. Also, secured to each blade 27 is a plate-like member 29 which carries a plurality of angularly spaced blades 31 which are shorter in length than the blades 27. The blades 27 are positioned closer to the passageways 17 than the relatively short blades 31, as shown.

Wood W is fed to the side of the disc 14 carrying the blades 16 by a chute 32 whereupon it is cut into chips by the knives 16. A tangential outlet 33 is provided for the chip receiving chamber 24 for discharging the chips, therefrom. Also, a circumferential outlet 34 is provided for the plenum chamber 26 adjacent and alongside the tangential outlet 33 for discharging air from the plenum chamber. Communicating with the outlets 33 and 34 is a discharge conduit 36 which receives the chips discharged through the tangential outlet 33 and the air discharged through the circumferential outlet 34 whereby the air discharged through the outlet 34 aids in conveying the chips through the discharge conduit 36. As shown in FIG. 2, the discharge end of the plenum chamber 26 is directed inwardly toward the tangential outlet 33 whereby air discharged from the circumferential outlet 34 contacts the chips discharged through the outlet 33 at an angle to prevent channelling of the air.

The arcuate wall section 23 extends from a point adjacent the outlets 33 and 34 to the point that the wood W is fed to the disc, as shown in FIG. 2, whereby the chips pass through the chip receiving chamber 24 while air is forced through the plenum chamber 26. The circumferential outlet 34 is separated from the tangential outlet 33 by a continuation 23 of the arcuate wall section 23 whereby the air discharged from the plenum chamber 26 does not engage the chips until they are introduced into the discharge conduit 36. Also, as shown in FIG. 2, the portion of the outer housing 18 extending in advance of the arcuate wall section 23 and between the tangential outlet 33 and the arcuate wall section 23 is involute in shape as at 18 whereby the upper half of the apparatus shown in FIG. 2 serves as a blower to introduce air into the chip receiving chamber 24 and into the plenum chamber 26. On the other hand, the lower half of the apparatus shown in FIG. 2 performs the function of a wood chipper. Accordingly, the portion of the outer housing 18 and the portion of the arcuate wall section 23 extending from a point adjacent the tangential outlet and the circumferential outlet to the point that wood is fed into the disc 14 is generally circular, as shown.

From the foregoing description, the operation of our improved wood chipper will be readily understood. Wood W is fed into the chute 32 whereupon it is cut into chips by the knives 16. The chips pass through the openings 17 into the chip receiving chamber 24. As the disc 14 is rotated, air is drawn inwardly of the housing 18 by the angularly spaced blades 27 and 31. Since the upper portion of the apparatus shown in FIG. 2 is free of chips and is surrounded by the involute section 18 of the outer housing 18, this portion of the apparatus operates as a blower to introduced air into the plenum chamber 26 and to introduce air into the chip receiving chamber 24 for conveying the chips therethrough and then outwardly through the tangential outlet 33.

The chips are conveyed through the chip receiving chamber 24 by the kinetic energy possessed by the moving chips and by the air drawn inwardly of the chip receiving chamber through the inlet opening 22. Due to the fact that the arcuate wall section 23 is circular, the blades 27 and 31 remain relatively close to the inner surface thereof, as shown in FIG. 2, thereby preventing the chips from entering the small space between the arcuate wall and the blades. As the chips are discharged from the tangential outlet 33, they are engaged by the air discharged from the plenum chamber 26 through the outlet 34 whereby this air aids in conveying the chips through the discharge conduit 36. Since the arcuate wall section 23 is provided with an extension 23* which separates the outlets 33 and 34 from each other, the air discharged through the circumferential outlet 34 does not engage the chips until they are introduced into the discharge conduit 36.

From the foregoing, it will be seen that we have devised an improved wood chipper which is extremely simple of construction and one in which an angularly disposed portion thereof serves as a blower for introducing air into the chip receiving chamber and the plenum chamber while another angularly disposed portion thereof performs the function of a wood chipper. By providing the arcuate wall section 23 which separates the wood receiving chamber from the plenum chamber, we not only provide an efficient blower which aids in conveying the chips, but also provide a compact, centrally disposed chip receiving chamber which is positioned close to the chip conveying blades, thereby preventing the chips from passing between the conveying blades and the arcuate wall section. Furthermore, by providing a plenum chamber outwardly of the chip receiving chamber and the arcuate wall therebetween, a common blower unit is employed for both the plenum chamber and the chip receiving chamber.

While we have shown our invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and we desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What we claim is:

1. In a wood chipper embodying rotary disc having angularly spaced knives and angularly spaced passageways therethrough together with means to feed wood to one side of the disc whereby the wood is cut into chips which pass through the passageways to the other side of the disc,

(a) an outer housing surrounding said other side of the disc and spaced radially and outwardly from the periphery of the disc,

(b) an arcuate wall section surrounding a portion of said other side of the disc inwardly of said outer housing to define a chip receiving chamber inwardly of said arcuate wall section and a plenum chamber between said arcuate wall section and said outer housing,

(c) angularly spaced blades carried by said other side of the disc and disposed to rotate within said arcuate wall section with a relatively close fit to convey chips through said chip receiving chamber,

(d) a tangential outlet for said chip receiving chamber for discharging chips therefrom,

(e) a circumferential outlet for said plenum chamber adjacent and alongside said tangential outlet for discharging air therefrom,

(if) said arcuate wall section extending from a point adjacent said tangential outlet and said circumferential outlet to the point that wood is fed to the disc so that the chips pass through said chip receiving chamber while air is forced through said plenum chamber, and

(g) a discharge conduit communicating with said tangential outlet and said circumferential outlet to receive chips discharged through said tangential outlet and air discharged through said circumferential outlet whereby the air discharged through said circumferential outlet aids in conveying the chips through said discharge conduit.

2. In a wood chipper as defined in claim 1 in which the disharge end of said plenum chamber is directed inwardly toward the tangential outlet whereby air discharged from said circumferential outlet contacts the chips discharged through said tangential outlet at an angle.

3. In a Wood chipper as defined in claim 1 in which the circumferential outlet is separated from the tangential outlet by a continuation of said arcuate wall section whereby the air discharged from the plenum chamber does not engage the chips until they are introduced into the discharge conduit.

4. In a wood chipper as defined in claim 1 in which a plurality of said angularly spaced blades extend radially between adjacent angularly spaced passageways.

5. In a wood chipper as defined in claim 4 in which the blades nearest the trailing edges of said angularly spaced passageways extend inwardly of the other blades.

6. In a wood chipper as defined in claim 1 in which the portion of the outer housing extending in advance of said arcuate wall section and between said tangential outlet and said arcuate wall section is involute in shape.

7. In a wood chipper as defined in claim 1 in which the portion of said outer housing and the portion of said arcuate wall section extending from a point adjacent said tangential outlet and said circumferential outlet to the point that wood is fed to the disc is generally circular.

References Cited UNITED STATES PATENTS 1,697,925 1/1929 McKay 146-107 3,123,311 3/1964 Fontaine 241-278 3,346,027 10/1967 Kirsten 144-176 GERALD A. DOST, Primary Examiner. 

1. IN A WOOD CHIPPER EMBODYING ROTARY DISC HAVING ANGULARLY SPACED KNIVES AND ANGULARLY SPACED PASSAGEWAYS THERETHROUGH TOGETHER WITH MEANS TO FEED WOOD TO ONE SIDE OF THE DISC WHEREBY THE WOOD IS CUT INTO CHIPS WHICH PASS THROUGH THE PASSAGEWAYS TO THE OTHER SIDE OF THE DISC, (A) AN OUTER HOUSING SURROUNDING SAID OTHER SIDE OF THE DISC AND SPACED RADIALLY AND OUTWARDLY FROM THE PERIPHERY OF THE DISC, (B) AN ARCUATE WALL SECTION SURROUNDING A PORTION OF SAID OTHER SIDE OF THE DISC INWARDLY OF SAID OUTER HOUSING TO DEFINE A CHIP RECEIVING CHAMBER INWARDLY OF SAID ARCUATE WALL SECTION AND A PLENUM CHAMBER BETWEEN SAID ARCUATE WALL SECTION AND SAID OUTER HOUSING, (C) ANGULARLY SPACED BLADES CARRIED BY SAID OTHER SIDE OF THE DISC AND DISPOSED TO ROTATE WITHIN SAID ARCUATE WALL SECTION WITH A RELATIVELY CLOSE FIT TO CONVEY CHIPS THROUGH SAID CHIP RECEIVING CHAMBER, (D) A TANGENTIAL OUTLET FOR SAID CHIP RECEIVING CHAMBER FOR DISCHARGING CHIPS THEREFROM, (E) A CIRCUMFERENTIAL OUTLET FOR SAID PLENUM CHAMBER ADJACENT AND ALONGSIDE SAID TANGENTIAL OUTLET FOR DISCHARGING AIR THEREFROM, (F) SAID ARCUATE WALL SECTION EXTENDING FROM A POINT ADJACENT SAID TANGENTIAL OUTLET AND SAID CIRCUMFERENTIAL OUTLET TO THE POINT THAT WOOD IS FED TO THE DISC SO THAT THE CHIPS PASS THROUGH SAID CHIP RECEIVING CHAMBER WHILE AIR IS FORCED THROUGH SAID PLENUM CHAMBER, AND (G) A DISCHARGE CONDUIT COMMUNICATING WITH SAID TANGENTIAL OUTLET AND SAID CIRCUMFERENTIAL OUTLET TO RECEIVE CHIPS DISCHARGED THROUGH SAID TANGENTIAL OUTLET AND AIR DISCHARGED THROUGH SAID CIRCUMFERENTIAL OUTLET WHEREBY THE AIR DISCHARGED THROUGH SAID CIRCUMFERENTIAL OUTLET AIDS IN CONVEYING THE CHIPS THROUGH SAID DISCHARGE CONDUIT. 